The present invention relates to an optical image and transmission composite assembly, especially to an image-input optical module provided with transmission unit for transmitting and guiding functions, thus modularizing the optical module and the transmission unit, and reducing cost.
The flat bed image scanners are popular computer peripheral for scanning the text, chart or graphic from book or magazine into computer accessible data. The prior art flat bed image scanners generally comprise an image input means, a transmission unit, an image processing circuit, a transparent scanning window and a shell. The transmission unit occupies considerable space in the flat bed image scanner. Therefore, the improvement of transmission unit is important design issues for the flat bed image scanners.
As shown in FIG. 1, a prior art image input means 1a generally comprises a light source, a reflection mirror set, a lens, and an image sensor (not shown). The transmission unit 2a generally comprises a stepper motor 20a, a wheel set 21a, a idler wheel 22a, a timing belt 23a and a sliding shaft 24a. 
The operation principle of the flat bed image scanner is described as follows. The document to be scanned is placed atop the transparent scanning window and then illuminated by the light source of the image input means 1a. The reflected light from the document is then guided to the image sensor (not shown) by the reflection mirror set and the lens (both not shown). The image sensor generates electrical signal corresponding to the received light and then sends the signal to the image processing circuit to digitize. After the image sensor (not shown) finishes scanning one row of image, the transmission unit 2a moves the image input means 1a next region to be scanned. Repeat said processes until all area of document has been scanned.
Moreover, as shown in FIG. 1, the stepper motor 20a and the wheel set 21a of the transmission unit 2a are retained on the shell of the flat bed image scanner. The wheel set 21a is located at one end of the timing belt 23a and driven by the timing belt 23a such that the image input means 1a is sliding along the sliding shaft 24a to complete the image scanning.
However, in above-mentioned flat bed image scanner, the image input means 1a and the transmission unit 2a are separately arranged and the transmission unit 2a are retained on the shell of the flat bed image scanner. Therefore, considerable space is wasted. Moreover, the flat bed image scanner is hard to disassemble and assemble.
It is the object of the present invention to provide an optical image and transmission composite assembly wherein the optical module is provided with transmission unit for transmitting and guiding functions, thus modularizing the optical module and the transmission unit, and reducing cost.
To achieve above object, the present invention provides an optical image and transmission composite assembly for a scanner. The optical image and transmission composite assembly comprises an optical module, a transmission unit and a guiding unit. The optical module has a light source, a reflection mirror set, a lens and an image sensor. The transmission unit has a stepper motor and is arranged on the optical module. The stepper motor has a driving wheel engaged to a first driven wheel and the first driven wheel is engaged to a tooth bar. The guiding unit has a second driven wheel engaged to the first driven wheel and also engaged to another tooth bar.
In another aspect of the invention, the guiding unit has a female guiding stage and a male guiding stage fit with the female guiding stage, and is functioned to guide the optical module.
The various objects and advantages of the present invention will be more readily understood from the following detailed description when read in conjunction with the appended drawing, in which: